Jefferson County - East-West Gateway Coordinating Council

A Regional Overview All-Hazard Mitigation Plan 121
Arnold
Byrnes Mill
Cedar Hill Lakes
Crystal City
DeSoto
Festus
Herculaneum
Kimmswick
Pevely
Scotsdale
Consequences from riverine and flash flooding could be catastrophic in terms of safety of
lives and property. Riverine flooding is considered a primary hazard for the County.
Significant Mississippi River flooding inundated the above communities in July 1947, July
1951, August 1993, and May 1995. Significant Meramec River flooding also inundated
Byrnes Mill and Arnold in May 1973, December 1982, August 1993, and April 1994.
During the 1993 flood, in Jefferson County, $1,527,199 in public assistance was paid to
claimants as a result of flood damage. In one community, the wastewater treatment plant
was inundated by floodwaters; the community is currently constructing a levee and
floodwall to protect the new infrastructure. Significant flash flooding in the Meramec,
Bourbeuse and Big River basins from an intense rainfall on May 7, 2000. The flooding
resulted in two deaths, extensive damage to structures, roads and bridges and major
economic losses from communities and businesses throughout the area. Communities
including Byrnes Mill and Eureka (St. Louis County) were overwhelmed by the deluge that
consisted of a thunderstorm that delivered up 15 inches of rain in 13 hours. A Federal
Disaster declaration was made (DR-1328); damages and losses incurred totaled
$483,511.22 in individual assistance, $473,000 in small business loans, and $574,002.26
in public assistance. In 2003, flash flooding and a severe tornado resulted in inundation,
one death and property storm damage in DeSoto with an estimated at $1 million dollars in
damage.
Consequences from earthquakes (and cascading hazards) could also be catastrophic in
terms of human lives and property in the event of a larger magnitude earthquake (in the
range of 6.7 to 8.6). The nearby New Madrid Fault Zone has the potential to produce an
earthquake of this magnitude and cause damage similar to the earthquake that struck the
San Francisco Bay region during the World Series, killing 63 people and causing $6 billion
of property damage. The nearby the Wabash Valley Fault and the fault zones in the vicinity
of Farmington (including Big River Fault and the St. Genevieve Fault Zone) are also capable
of producing lesser magnitude earthquakes. The earthquake hazard is also considered a
primary hazard. Certain regions within the County are more susceptible to greater damage
from earthquakes due to their position within the soil liquefaction zone, as identified by
Missouri Department of Natural Resources, Geological Survey Resource Assessment
Division, Earthquake Hazards Map of the St. Louis Metro Area. Areas outside of the soil
liquefaction zone will most likely be impacted from an earthquake, but probably to a lesser
degree. These incorporated communities within Jefferson County that exhibit a unique